Ophthalmic compositions comprising ciclosporin

ABSTRACT

The present invention relates to compositions in the form of a clear solution comprising ciclosporin with low residual water content and 1-perfluorobutyl-pentane. The compositions may be used for topical administration to the eye.

BACKGROUND OF THE INVENTION

Ciclosporin is a challenging compound to formulate and to deliver due to its extremely poor solubility in water, and relatively large molecular size. Solubilizing excipients such as surfactants and organic or oil-based solvents are typically required in formulations of this compound.

Many ophthalmic formulations of ciclosporin disclosed in the art are based on oil-in-water emulsions in which the ciclosporin is dissolved in the oily phase (e.g. castor oil). One of the disadvantages of using organic or oil-based solvents or surfactants as a solubilizing agent in ophthalmic formulations is that these may often cause eye irritation such as pain, or stinging sensation when administered to the eye and may be poorly tolerated as a result. In the case of oily excipients, these may also have an inherent negative impact on vision (e.g. blurring) especially when present in substantial amounts, due to substantial differences in refractive index compared to that of physiological tear fluid. Oil-in-water emulsion formulations are also disadvantaged in that they may have limited drug load capacity, since while the active ingredient may have some solubility in the oil phase, this phase is only dispersed in the coherent aqueous phase, so that maximum overall drug concentration in the formulation is limited.

WO2011/073134A1 discloses pharmaceutical compositions in the form of solutions comprising ciclosporin and a semifluorinated alkane as a liquid vehicle which may be administered to the eye of a patient, such as for the treatment of keratoconjunctivitis. It is disclosed ciclosporin has a solubility of 2.54 g/L in the semifluorinated alkane 1-perfluorobutyl-pentane (F4H5) in the absence of any co-solvent. WO2011/073134A1 further teaches that with a small amount of ethanol as a co-solvent, the solubility of ciclosporin in F4H5 increases markedly, for example to 5.65 g/L when 1.0 wt % of ethanol is included in the composition. Ethanol is, generally speaking, not very tolerated by the human eye however it is mentioned that inclusion of a small amount of ethanol such as 1 wt % does not negatively affect tolerability. It would be an advantage, nevertheless, if the use of an additional further excipient and a co-solvent such as ethanol can be avoided.

It is thus an object of the present invention to provide improved compositions comprising ciclosporin which overcome these limitations of the prior art formulations. Further objects of the invention will be clear on the basis of the following description of the invention, examples and claims.

SUMMARY OF THE INVENTION

The invention provides a composition in the form of a clear solution comprising ciclosporin dissolved in 1-perfluorobutyl-pentane, wherein the composition is essentially free of a co-solvent and the concentration of ciclosporin is greater than about 2.6 mg/mL at 15-25° C., or greater than about 3.0 mg/mL. In a further aspect, the residual water content of the composition is less than about 0.04 mg/mL, or less than about 0.03 mg/mL.

In another aspect, the invention provides a composition in the form of a clear solution, comprising ciclosporin dissolved in 1-perfluorobutyl-pentane, wherein the composition is essentially free of a co-solvent, and wherein the composition has a residual water content of less than about 0.04 mg/ml, or less than about 0.03 mg/mL.

Preferably, the composition of the invention is essentially free of ethanol as a co-solvent. The composition is also preferably thermodynamically stable at 15-25° C.

Furthermore, the invention provides medical uses of these compositions, in particular for use for the treatment of keratoconjunctivitis sicca, meibomian gland dysfunction, or a symptom thereof. In one embodiment, these compositions are for ophthalmic use and are topically administered to the eye, such as in the form of eye drops.

In yet a further aspect, the invention provides for a composition that is obtainable by dissolving ciclosporin with a water content of less than about 1.6 wt %, or more preferably, by dissolving ciclosporin with a water content of less than about 1.0 wt %, based on the total weight of the ciclosporin, in 1-perfluorobutyl-pentane. A method of preparing a composition of the invention is also provided, the method comprising the steps of a) providing ciclosporin with a water content of less than about 1.6 wt %, or more preferably less than about 1.0 wt %, based on the total weight of the ciclosporin, and b) dissolving said ciclosporin in 1-perfluorobutyl-pentane.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts the water sorption of ciclosporin obtained from sorption calorimetry at 25° C. The inset is a zoomed area of the ciclosporin sorption isotherm at the higher relative humidity (RH) levels.

FIG. 2A depicts the solubility of ciclosporin in 1-perfluorobutyl-pentane as a function of relative humidity.

FIG. 2B depicts the solubility of ciclosporin in 1-perfluorobutyl-pentane as a function of water content of the ciclosporin.

DETAILED DESCRIPTION OF THE INVENTION

In a first aspect, the invention relates to a composition in the form of a clear solution comprising ciclosporin dissolved in 1-perfluorobutyl-pentane, wherein the composition is essentially free of a co-solvent and the concentration of ciclosporin, as determined at 15-25° C., is greater than about 2.6 mg/mL, or more preferably, greater than 3.0 mg/mL.

Ciclosporin (synonyms include cyclosporin A, CsA, or cyclosporine) is a cyclic nonribosomal peptide comprising 11 amino acids with the empirical formula C₆₂H₁₁₁N₁₁O₁₂ and molecular weight of 1202.61. It is an immunosuppressant drug that is widely used in post-allergenic organ transplant, to reduce the activity of the patient's immune system and thereby, the risk of organ rejection. Ciclosporin is typically provided as a colourless or white powder.

Preferably, the ciclosporin as used for the formulation of the composition and any of the embodiments or preferences as described herein has a water content of less than about 1.6 wt %, based on the total weight of ciclosporin. In another embodiment, the composition of the invention comprises of a total residual water content of less than about 0.04 mg/mL. More preferably, the ciclosporin as used for the formulation of the composition and any of the embodiments or preferences as described herein has a water content of less than about 1.0 wt %, based on the total weight of ciclosporin. In another embodiment, the composition of the invention comprises of a total residual water content of less than about 0.03 mg/mL. In yet a further embodiment, the composition comprises no residual water content.

The term residual water content as used herein refers to the fraction or trace amount of water that may be present in the composition originating from the composition components, such as ciclosporin and 1-perfluorobutyl-pentane.

The predominant contribution to residual water content in the composition can be attributed to water sorption or association with ciclosporin (e.g. not limited to, but for example derived from manufacturing process, or its transport and storage). Ciclosporin, as is usually available for medicinal use and formulation typically has a water content of about 1.6 wt % based on the weight of ciclosporin. The water solubility in 1-perfluorobutylpentane is on the other hand essentially negligible i.e. in very low amounts such as less than 1.20×10⁻⁵ wt % based on weight of 1-perfluorobutylpentane.

The residual water content of ciclosporin, 1-perfluorobutyl-pentane, or of the composition of the invention comprising ciclosporin dissolved in 1-perfluorobutyl-pentane may be determined using methods and/or apparatus known in the art for moisture analysis, for example, but not limited to methods such as standard Karl-Fischer titration e.g. volumetric or coulometric.

It has been found that unexpectedly high concentrations of ciclosporin, such as greater than about 2.6 mg/mL, or more preferably greater than about 3.0 mg/mL at room temperature (i.e. 15-25° C.), may be dissolved in 1-perfluorobutyl-pentane without the need of a co-solvent. This has been observed in particular when the total residual water content of the compositions is less than about 0.04 mg/mL, in particularly less than 0.03 mg/mL, such as when the residual water content of ciclosporin is low.

While co-solvents may be useful as an aid for solubilizing ciclosporin and enable higher concentration formulations of ciclosporin to be obtained, it would be preferable if their use can be avoided. In particular, in context of ophthalmic use, co-solvents in the form of liquid solubilizing excipients such as surfactants or non-aqueous organic solvents may cause eye irritation or eye discomfort (e.g. blurred vision, or pain) when topically administered to the eye. Examples of co-solvents which may be used to help solubilize ciclosporin include oils such as glyceride or triglyceride oils (e.g. soybean oil, olive oil, sesame oil, cotton seed oil, castor oil or sweet almond oil), mineral oils (e.g. petrolatum or liquid paraffin), liquid oily fatty acids, fatty alcohols or sorbitol esters, or organic solvents e.g. glycerol, polyethylene glycol, propylene glycol or ethanol.

In a preferred embodiment, the composition of the invention is essentially free of a co-solvent such as defined above. As used herein, the term ‘essentially free’ means that there is no co-solvent in the composition, and if present then in trace or residual amounts such as to confer no technical advantage or relevance in respect of the object of the invention. Most preferably, the compositions as described herein are essentially free of ethanol as a co-solvent.

The absence of an organic co-solvent such as ethanol offers the advantages of a simpler two component formulation (essentially consisting of ciclosporin and 1-perfluorobutyl-pentane) as compared to a more complex three component formulation additionally comprising a co-solvent such as ethanol, in terms of factors such as cost, manufacturing, handling, packaging, and also patient compliance.

The higher concentrations of ciclosporin that may be obtained may offer advantages in terms of reducing the dosing frequency required by patients, and may also lead to more effective delivery of ciclosporin to the intended target tissue, for example to the eye. The compositions according to the invention may comprise of ciclosporin dissolved in 1-perfluorobutylpentane at a concentration of greater than about 2.6 mg/mL, as determined at room temperature or ambient temperature, i.e. about 15-25° C. In further embodiments, the concentration of ciclosporin in the composition at 15-25° C. is preferably greater than about 3.0 mg/mL, or may be in the range of from about 2.6 to 4.8 mg/mL, or 2.8 to 4.8 mg/mL, or preferably from about 3.0 to 4.8 mg/mL. In a further preferred embodiment, the concentration of dissolved ciclosporin is about 4.0 mg/mL as determined at 15-25° C. The concentration of ciclosporin dissolved in the solution may be quantified using methods known in the art, such as HPLC. As used herein, the term ‘about’ in reference or connection to a parameter such as the concentration, or concentration range of dissolved ciclosporin, or in relation to the residual water content of ciclosporin, based on the total weight of the ciclosporin, or in relation to the total residual water content in a composition according to the invention, may include the precise value as well as any value falling within the degree of variability usually observed in measuring or determining these parameters using the standard techniques and equipment known in the art and field.

In one embodiment, the ciclosporin as used herein is amorphous and is not crystalline or predominantly in any specific crystal form. Preferably, the ciclosporin that is dissolved in the 1-perfluorobutyl-pentane is obtained by a step of drying to reduce or to remove residual water from the ciclosporin. For example, the ciclosporin used in the preparation of a composition according to the invention, such as with a total residual water content of about 1.0%, is obtained by drying using drying methods known in the art such as drying under vacuum, drying in the presence of a desiccant or a drying agent.

A clear solution, as understood herein, refers to a liquid solution in which all solutes are fully dissolvable or dissolved under room temperature conditions i.e. between 15-25° C. The clear solution does not comprise of any particulate or solid phase components, for example undissolved ciclosporin and preferably has a refractive index approximate to that of water (i.e. 1.333) at room temperature. In one embodiment, the clear solution as presented by the composition of the invention may have a refractive index of between about 1.3 to 1.4.

In particular, the clear solution is thermodynamically stable between 15-25° C., meaning that under equilibrium, all of the dissolved components, including ciclosporin, remain in the dissolved state and that no phase separation, precipitation or changes to the physical form of the solution occurs. Preferably, the composition in the form of a clear solution according to the invention as described herein is thermodynamically stable when stored at 15-25° C. i.e. room temperature for a period of time such as at least about 2 weeks, or about 1 month, or 3 months, or at least about 6 months. Moreover, the invention may provide a composition which when stored at lower temperatures, such as under refrigeration, for example at temperatures between 0-10° C. may partially precipitate, but when brought back to 15-25° C. (room temperature) returns to a thermodynamically stable and clear solution with all previously precipitated components dissolved again.

The liquid carrier of the composition according to the invention, 1-perfluorobutyl-pentane, is a semifluorinated alkane with the chemical formula F(CF₂)₄(CH₂)₅H. It is an inert, water-insoluble liquid, with a density of 1.284 g/cm³ at 25° C. and refractive index of 1.3204 at 20° C. Alternative nomenclature for this compound includes F4H5, wherein F denote a linear perfluorinated alkane segment comprising 4 carbon atoms and wherein H denotes a linear and non-fluorinated alkane hydrocarbon segment of 5 carbon atoms.

The 1-perfluorobutyl-pentane as featured in any of the compositions or methods described herein is preferably essentially free of water. In such case, the presence of residual water in the composition according to the invention is derived from the ciclosporin or optionally, if present, one or more excipients that is functionally not a co-solvent. More preferably, the 1-perfluorobutyl-pentane does not comprise of any water, or has a water content of no more than the maximal solubility of water in 1-perfluorobutyl-pentane, for example, has a water-content of less than 1.6×10⁻⁴ mg/mL as determined by methods known in the art for moisture analysis, such as Karl-Fischer titration methods.

In another aspect, the invention provides a composition in the form of a clear solution comprising ciclosporin dissolved in 1-perfluorobutyl-pentane, wherein the composition is essentially free of a co-solvent, and wherein the composition has a residual water content of less than about 0.04 mg/ml.

In a further embodiment, the invention provides a composition in the form of a clear solution comprising ciclosporin dissolved in 1-perfluorobutyl-pentane, wherein the composition is essentially free of a co-solvent, and wherein the composition has a residual water content of less than about 0.03 mg/ml.

In further embodiments, the composition may have a total residual water content of less than 0.03 mg/mL or of less than 0.025 mg/mL, or of less than 0.02 mg/mL, or of less than 0.015 mg/mL, or less than 0.01 mg/mL.

In particular, the relative ratio of ciclosporin to residual water content as featured in the compositions as described in any of the embodiments and featured herein may be at least greater than about 65 to 1, or preferably, greater than 100 to 1, or greater than 200 to 1.

The concentration of ciclosporin in such compositions at 15-25° C. is preferably from about 0.5 to 4.8 mg/mL. In further embodiments, the concentration of ciclosporin as determined at room temperature of the composition may be in the range of from about 2.6 to 4.8 mg/mL, or preferably from about 3.0 to 4.8 mg/mL. In a particularly further preferred embodiment, the concentration of dissolved ciclosporin at 15-25° C. is about 4.0 mg/mL. Lower concentrations of ciclosporin, such as from about 0.5 to 2.6 mg/mL, or from the range of about 0.5 to 1.0 mg/mL of ciclosporin dissolved in 1-perfluorobutyl-pentane may also contemplated in for the invention. Due to the dependence of solubility in relation to temperature, there is general tendency for active ingredients such as ciclosporin to precipitate out of solution when the solution is stored at lower temperature conditions. The low water content of the ciclosporin such as described for the invention advantageously may provide improved physical stability to the solution formed in 1-perfluorobutylpentane, for example even when the solution is stored at lower temperatures, such as under refrigeration (e.g. at 0-10° C.), any precipitation that may occur will easily dissolve again when the composition is brought back to 15-25° C. (room temperature).

In yet a further embodiment, the composition as described in any of the embodiments or preferences featured herein, including any combinations thereof, consists essentially of 1-perfluorobutyl-pentane and ciclosporin and has a residual water content in an amount of less than about 0.04 mg/mL.

In yet another embodiment, the composition as described in any of the embodiments or preferences featured herein, including any combinations thereof, consists essentially of 1-perfluorobutyl-pentane and ciclosporin and has a residual water content in an amount of less than about 0.03 mg/mL.

The residual water content of the composition may be primarily attributed to the residual water content of ciclosporin, for example, wherein at least 99% of the residual water content of the composition can be attributed to ciclosporin. As used herein, the term “consists” and related terms “consisting” or “consist” is to be understood as meaning that no other features, other than those prefaced by the term are present. The term ‘essentially’ means if present then in trace or residual amounts such as to confer no technical advantage or relevance in respect of the object of the invention.

The composition as described in any of the above embodiments, and embodiments herein, including any combinations or preferences thereof, may be used as a medicine, and for therapeutic use. The use of said compositions in the manufacture of a medicament or medicine for the treatment of a patient in need thereof is also provided for in the context of the present invention.

Particular preferred is the use of the composition for the treatment of keratoconjunctivitis sicca, or a symptom thereof. Keratoconjunctivitis sicca is also known as dry eye disease or syndrome, or dysfunctional tear syndrome. A patient having keratoconjunctivitis sicca may experience any one of, or a combination of tear hyperosmolarity, tear film instability or abnormalities in the lipid layer composition of the tear film. Aqueous-deficient dry eye disease, evaporative dry eye disease, Sjögren syndrome, lacrimal gland insufficiency, meibomian gland dysfunction as understood herein may be considered to be within the scope, for example as sub-types, of keratoconjunctivitis sicca.

Symptoms of keratoconjunctivitis may include any one, or combination of the following: a dry, scratchy, gritty, or sandy feeling in the eye; foreign body sensation; pain or soreness; stinging or burning; itching; increased blinking; eye fatigue; photophobia; blurry vision; redness; mucus discharge; contact lens intolerance; excessive reflex tearing. It is understood that not all patients suffering from keratoconjunctivitis sicca may exhibit all symptoms simultaneously. Hence, there is currently no uniform set of criteria for diagnosing the disease. It is however important to note that, within the scope of the present invention, any of the aspects, symptoms or pathophysiological consequences of keratoconjunctivitis sicca may be addressed.

Also preferred is the use of the composition as defined in any of the embodiments described herein for the treatment of meibomian gland dysfunction, or a symptom thereof. Meibomian gland dysfunction may be characterized by gland obstruction and clogging through hyperkeratinisation of the gland and increased viscosity of the meibum lipid secretions of the meibomian gland ducts. The quantitative or qualitative secretion of the lipid components required for the tear film may be altered in the case of patients with meibomian gland dysfunction. This may lead to a failure in forming a stable and continuous tear film, which may be further followed by evaporative loss and hyperosmolarity. Meibomian gland dysfunction can arise from a primary lid-margin related disease or a secondary disease arising from systemic disorders such as acne rosacea, or seborrheic dermatitis. In addition to any one of the symptoms as described for keratoconjunctivitis sicca as described above, patients with meibomian gland dysfunction may also experience symptoms including any one or combination thereof, of itching, redness, swelling, pain or soreness, discharge accumulation or crusting at the eye lid margins.

The compositions according to the above uses are preferably ophthalmic compositions that are topically administered to the surface of the eye and to any such region or tissue of the eye that may be accessible to topical administration, such as to the cornea or conjunctiva.

The compositions of the invention as described herein may be provided as part of a kit, for example a kit comprising the composition and a container adapted for holding the composition, wherein the container has a dispensing means adapted for topical administration of the composition to the eye or ophthalmic tissue. Optionally, such kit may comprise a water-desiccant or water-desiccating means to safeguard a stable residual water content, for example during storage. An increase in residual water content may the affect solubility of ciclosporin which in turn may affect the stability of the composition and may result in precipitation. Further optionally, instructions for use of the kit in the treatment of keratoconjunctivitis sicca or a symptom thereof, or for use of the kit in the treatment of meibomian gland dysfunction or a symptom thereof may also be included as part of the kit.

In another aspect of the invention, the invention provides for a composition obtainable by dissolving ciclosporin with a water content of less than about 1.6 wt %, based on the total weight of ciclosporin, in 1-perfluorobutyl-pentane. In yet another aspect of the invention, the invention provides for a composition obtainable by dissolving ciclosporin with a water content of less than about 1.0 wt %, based on the total weight of ciclosporin, in 1-perfluorobutyl-pentane. The ciclosporin used for obtaining such compositions may in other embodiments have a water content of less than about 0.8 wt %, or 0.6 wt % or 0.5 wt % or 0.4 wt %, or 0.3 wt %. Particularly preferred is the use of ciclosporin with a water content of 0.4 wt % or less, based on the weight of ciclosporin to obtain a solution in 1-perfluorobutyl-pentane, preferably a clear solution.

Preferably, the composition, including any of its embodiments or preferences as described above is obtained wherein the ciclosporin is dissolved in 1-perfluorobutyl-pentane in the absence of a co-solvent, for example in the absence of ethanol or any of the co-solvents mentioned above. The concentration of ciclosporin that may be dissolved at 15-25° C. to obtain the composition is preferably greater than 2.6 mg/mL. In further embodiments, composition obtained may have a concentration of ciclosporin at 15-25° C. greater than 3.0 mg/mL, or in the range of from about 2.6 to 4.8 mg/mL, or preferably from about 3.0 to 4.8 mg/mL. In a further preferred embodiment, the concentration of dissolved ciclosporin is about 4.0 mg/mL.

Preferably, the composition obtained, including any of its embodiments or preferences as described above provides a clear solution that is thermodynamically stable at 15-25° C.

The composition obtainable according to any of the above embodiments, may be used as a medicament, or used for the manufacture of a medicament. In particular, the composition may be used for use in the treatment of keratoconjunctivitis sicca or a symptom thereof; or for use in the treatment of meibomian gland dysfunction or a symptom thereof. Preferably, the compositions obtainable according to any of the embodiments described herein are ophthalmic compositions, and are used for topical administration to the surface of the eye and to any such region or tissue of the eye that may be accessible to topical administration, such as to the cornea or conjunctiva.

The invention further provides a method of preparing a composition as described in any of the above embodiments or preferences comprising the steps of a) providing ciclosporin with a water content of less than about 1.6 wt % based on the total weight of the ciclosporin, and b) dissolving said ciclosporin in 1-perfluorobutyl-pentane.

Further embodiments of this method may include a method of preparing compositions according to the following embodiments:

1. A composition in the form of a clear solution comprising ciclosporin dissolved in 1-perfluorobutyl-pentane, wherein the composition is essentially free of a co-solvent and the concentration of ciclosporin at 15-25° C. is greater than about 2.6 mg/mL.

2. The composition according to item 1, wherein the residual water content of the composition is less than about 0.04 mg/mL.

3. The composition according to any of items 1 or 2, wherein the concentration of ciclosporin at 15-25° C. is in the range of from about 2.6 to 4.8 mg/mL, or preferably from about 3.0 to 4.8 mg/mL.

4. A composition in the form of a clear solution comprising ciclosporin dissolved in 1-perfluorobutyl-pentane, wherein the composition is essentially free of a co-solvent, and wherein the composition has a residual water content of less than about 0.04 mg/mL.

5. The composition according to item 4, wherein the concentration of ciclosporin at 15-25° C. is from about 0.5 to 4.8 mg/mL.

6. The composition according any of items 1 to 5, wherein the co-solvent is ethanol.

7. The composition according to any of items 1-6, wherein the solution is thermodynamically stable at 15-25° C.

The invention moreover further provides a method of preparing a composition as described in any of the above embodiments or preferences, namely, a method of preparing a composition in the form of a clear solution comprising ciclosporin dissolved in 1-perfluorobutyl-pentane, and wherein the composition is essentially free of a co-solvent, the method comprising the steps of a) providing ciclosporin with a water content of less than about 1.0 wt % based on the total weight of the ciclosporin, and b) dissolving said ciclosporin in 1-perfluorobutyl-pentane.

In a further embodiment, step a) may be the provision of ciclosporin having a water content of less than about 0.8 wt %, or 0.7 wt %, or 0.6 wt %, or 0.5 wt % or preferably 0.4 wt % based on the weight of ciclosporin. In another embodiment, step a) may be the provision of ciclosporin having a water content of less than about 0.3 wt %, based on the weight of ciclosporin.

In yet further embodiments, the method as described above may be for preparing the following compositions:

1. A composition in the form of a clear solution comprising ciclosporin dissolved in 1-perfluorobutyl-pentane, wherein the composition is essentially free of a co-solvent, wherein the concentration of ciclosporin at 15-25° C. is from about 0.5 to 4.8 mg/mL, or more preferably about 0.5 to 3.0 mg/mL, or about 0.5 to 1.0 mg/mL.

2. A composition in the form of a clear solution comprising ciclosporin dissolved in 1-perfluorobutyl-pentane, wherein the composition is essentially free of a co-solvent, wherein the concentration of ciclosporin at 15-25° C. is in the range of from about 3.0 to 4.8 mg/mL.

3. The composition according to any of item 1 or 2, wherein the co-solvent is ethanol.

4. The composition according to any of items 1 to 3, wherein the solution is thermodynamically stable at 15-25° C.

Moreover, step a) of the method may comprise drying ciclosporin with a water content of about 1.6 wt % or greater than about 1.6 wt % based on the total weight of the ciclosporin.

The step of providing a ciclosporin with low residual water content, such as providing ciclosporin with a water content of less than about 1.0 wt % based on the total weight of the ciclosporin, may include a step of drying ciclosporin which has a higher water content, such as greater than 1.6 wt % based on the total weight of the ciclosporin, or greater than about 1.3 wt %, or about 1.4 wt % or about 1.5 wt %, based on the total weight of the ciclosporin.

In particular, the step of providing ciclosporin having a water content of less than about 1.0 wt %, 0.8 wt %, or 0.6 wt %, or preferably 0.4 wt % may include a step subjecting ciclosporin with a higher water content, preferably ciclosporin with a water content of about 1.6 wt %, or greater than 1.6 wt % based on the total weight of the ciclosporin, to a drying process. Methods of drying include, but are not limited to, drying the ciclosporin under vacuum, optionally in the presence of a water-desiccant or drying agent. The duration, and method of drying may be adapted in order to provide the targeted water content value of ciclosporin.

Further embodiments of the invention may be as follows:

1. A composition in the form of a clear solution comprising ciclosporin dissolved in 1-perfluorobutyl-pentane, wherein the composition is essentially free of a co-solvent, and wherein the composition has a residual water content of less than about 0.03 mg/mL.

2. The composition according to item 1, wherein the concentration of ciclosporin at 15-25° C. is from about 0.5 to 4.8 mg/mL.

3. The composition according to any preceding item 1 or 2, wherein the co-solvent is ethanol. 7.

4. The composition according to any preceding item, wherein the solution is thermodynamically stable at 15-25° C.

5. A composition according to any of the preceding items for use as a medicine.

6. The composition for use according to item 5, wherein the composition for use in the treatment of keratoconjunctivitis sicca or a symptom thereof; or for use in the treatment of meibomian gland dysfunction or a symptom thereof.

The following examples serve to illustrate the invention however these are not to be understood as restricting the scope of the invention.

EXAMPLES Example 1

Isothermal sorption calorimetry of ciclosporin at 25° C. was determined using a 28 mm two-chamber calorimetric cell inserted in a double-twin microcalorimeter. A dry sample, prepared by drying ciclosporin for one day under vacuum and over molecular sieves was placed in the upper (sorption) chamber and pure water was injected in the lower (vaporization) chamber. The water activity was calculated from the power of evaporated water registered in the vaporization chamber. It was found that ciclosporin may comprise of up to about 8 wt % water when exposed to a relative humidity of 99% RH.

FIG. 1 depicts the water sorption of ciclosporin obtained in sorption calorimetry at 25° C. The inset in the FIG. 1 is a zoomed area of the ciclosporin sorption isotherm at higher relative humidity (RH) levels. The water content of ciclosporin at 99.25% RH is approximately 7.41 wt %.

The solubility of ciclosporin in 1-perfluorobutyl-pentane was then determined as a function of its water content. Samples, dried as above were incubated for 5 days in desiccators at different fixed relative humidity at room temperature. The various relative humidity was regulated in the desiccators using saturated salt solutions (LiCl, MgCl₂, Mg(NO₃)₂, NaCl, K₂SO₄).

After incubation, excess ciclosporin of each sample were added to 1-perfluorobutyl-pentane and each sample was sealed and incubated for 3 days at constant agitation and temperature (room temperature) using an orbital shaker (IKA KS130 Basic, IKA®-Werke GmbH & Co). The resulting saturated solutions were filtered through a 0.2 μm PTFE syringe filter and diluted with acetonitrile (dilution factor of 50, 100 or 200) prior to determination of concentration by reversed phase HPLC-UV. The concentration of ciclosporin was calculated from calibration curves of standard solutions (10-100 μg/mL) prepared in acetonitrile. Based on the water sorption isotherm for ciclosporin, the solubility of ciclosporin in 1-perfluorobutyl-pentane as a function of the water content of ciclosporin could be determined. Table 1 depicts the dataset obtained.

TABLE 1 Relative Humidity CsA solubility in F4H5 (RH) % Water content, wt % (mg/mL) 0 0.00 4.75 ± 0.025 11 0.40 3.88 ± 0.027 33 0.76 2.75 ± 0.167 52 1.57 2.64 ± 0.099 53 1.60 2.00 ± 0.099 75 3.05 1.10 ± 0.061 97 6.00 0.90 ± 0.073 100 n.a. 0.52 ± 0.021

FIG. 2A depicts the solubility of ciclosporin in 1-perfluorobutyl-pentane as a function of relative humidity and FIG. 2B depicts the solubility of ciclosporin in 1-perfluorobutyl-pentane as a function of water content in the ciclosporin. It was observed that ciclosporin solubility in 1-perfluorobutyl-pentane starts to rapidly increase from when the water content residue in the ciclosporin is less than 1.6 wt % based on the total weight of the ciclosporin (FIG. 2B).

Karl-Fischer titration measurements of ciclosporin prior to the drying procedure (i.e. not treated) and after drying (i.e. for one day under vacuum and in the presence of molecular sieves, as described above) were also obtained, and maximal solubility in 1-perfluorobutyl-pentane were analogously determined. The results are summarized in Table 2.

TABLE 2 CsA Water Residual water CsA Solubility content content in CsA-F4H5 in F4H5 Ciclosporin (wt %) composition¹ (mg/mL) (mg/ml) As supplied 1.56 ± 0.06 0.0412 2.64 ± 0.10 Dried 0.40 0.0163 4.08 ± 0.39 ¹Values expressed excluding the negligible residual water in F4H5 of <1.6 × 10⁻⁴ mg/mL.

Significantly higher concentrations, i.e. greater than about 2.6 mg/mL, and up to 4.8 mg/mL of ciclosporin dissolved in 1-perfluorobutyl-pentane can be obtained when ciclosporin with a low and reduced water-content, such as less than about 1.6 wt %, and in particular less than 1.0 wt % is used. An approximately 1.6-fold unexpected increase in solubility of the ciclosporin in 1-perfluorobutyl-pentane was observed using ciclosporin with a reduced water content, of about 0.4 wt % based on the weight of the ciclosporin. 

1. A composition in the form of a clear solution comprising ciclosporin dissolved in 1-perfluorobutyl-pentane, wherein the composition is essentially free of a co-solvent, and wherein the composition has a residual water content of less than about 0.03 mg/mL.
 2. The composition according to claim 1, wherein the concentration of ciclosporin at 15-25° C. is from about 0.5 to 4.8 mg/mL.
 3. The composition according to any preceding claim, wherein the co-solvent is ethanol.
 4. The composition according to any preceding claim, wherein the solution is thermodynamically stable at 15-25° C.
 5. A composition according to any of the preceding claims for use as a medicine.
 6. The composition for use according to claim 5, wherein the composition for use in the treatment of keratoconjunctivitis sicca or a symptom thereof; or for use in the treatment of meibomian gland dysfunction or a symptom thereof.
 7. A composition obtainable by dissolving ciclosporin with a water content of less than about 1.0 wt %, based on the total weight of the ciclosporin, in 1-perfluorobutyl-pentane.
 8. The composition according to claim 7, wherein the ciclosporin is dissolved in the absence of a co-solvent.
 9. The composition according to claim 7 or 8, wherein the concentration of ciclosporin dissolved in the composition at 15-25° C. is greater than about 2.6 mg/mL.
 10. A method for the preparation of a composition in the form of a clear solution comprising ciclosporin dissolved in 1-perfluorobutyl-pentane, and wherein the composition is essentially free of a co-solvent, the method comprising the steps of a) providing ciclosporin with a water content of less than about 1.0 wt % based on the total weight of the ciclosporin, and b) dissolving said ciclosporin in 1-perfluorobutyl-pentane.
 11. The method according to claim 10, wherein step a) of providing ciclosporin with a water content of less than about 1.0 wt % based on the total weight of ciclosporin, comprises a step of drying ciclosporin with a water content of about 1.6 wt %, or greater than about 1.6 wt % based on the total weight of the ciclosporin.
 12. The method according to claim 10 or 11, wherein step a) comprises drying ciclosporin under vacuum, optionally in the presence of a water-desiccant or drying agent.
 13. A pharmaceutical kit, comprising: (i.) a composition as defined in any of the claim 1-4 or 7-9; (ii.) a container adapted for holding the composition, wherein the container has a dispensing means adapted for topical administration of the composition to the eye or ophthalmic tissue; (iii.) optionally, a water-desiccant; and (iv.) optionally, instructions for use of the kit in the treatment of kerato-conjunctivitis sicca or a symptom thereof, or for use of the kit in the treatment of meibomian gland dysfunction or a symptom thereof. 